/**
 ******************************************************************************
 * @addtogroup PIOS PIOS Core hardware abstraction layer
 * @{
 * @addtogroup   PIOS_USB_COM USB COM Functions
 * @brief PIOS USB COM implementation for CDC interfaces
 * @notes      This implements a CDC Serial Port
 * @{
 *
 * @file       pios_usb_com_cdc.c
 * @author     The OpenPilot Team, http://www.openpilot.org Copyright (C) 2010.
 * @brief      USB COM functions (STM32 dependent code)
 * @see        The GNU Public License (GPL) Version 3
 *
 *****************************************************************************/
/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
 * for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include "pios.h"

#ifdef PIOS_INCLUDE_USB_CDC

#include "pios_usb_cdc_priv.h"
#include "pios_usb_board_data.h" /* PIOS_BOARD_*_DATA_LENGTH */

/* STM32 USB Library Definitions */
#include "usb_lib.h"

static void PIOS_USB_CDC_RegisterTxCallback(uint32_t usbcdc_id, pios_com_callback tx_out_cb, uint32_t context);
static void PIOS_USB_CDC_RegisterRxCallback(uint32_t usbcdc_id, pios_com_callback rx_in_cb, uint32_t context);
static void PIOS_USB_CDC_TxStart(uint32_t usbcdc_id, uint16_t tx_bytes_avail);
static void PIOS_USB_CDC_RxStart(uint32_t usbcdc_id, uint16_t rx_bytes_avail);
static bool PIOS_USB_CDC_Available(uint32_t usbcdc_id);

const struct pios_com_driver pios_usb_cdc_com_driver = {
    .tx_start   = PIOS_USB_CDC_TxStart,
    .rx_start   = PIOS_USB_CDC_RxStart,
    .bind_tx_cb = PIOS_USB_CDC_RegisterTxCallback,
    .bind_rx_cb = PIOS_USB_CDC_RegisterRxCallback,
    .available  = PIOS_USB_CDC_Available,
};

enum pios_usb_cdc_dev_magic {
    PIOS_USB_CDC_DEV_MAGIC = 0xAABBCCDD,
};

struct pios_usb_cdc_dev {
    enum pios_usb_cdc_dev_magic   magic;
    const struct pios_usb_cdc_cfg *cfg;

    uint32_t lower_id;

    pios_com_callback rx_in_cb;
    uint32_t rx_in_context;
    pios_com_callback tx_out_cb;
    uint32_t tx_out_context;

    uint8_t  rx_packet_buffer[PIOS_USB_BOARD_CDC_DATA_LENGTH];
    /*
     * NOTE: This is -1 as somewhat of a hack.  It ensures that we always send packets
     * that are strictly < maxPacketSize for this interface which means we never have
     * to bother with zero length packets (ZLP).
     */
    uint8_t  tx_packet_buffer[PIOS_USB_BOARD_CDC_DATA_LENGTH - 1];

    uint32_t rx_dropped;
    uint32_t rx_oversize;
};

static bool PIOS_USB_CDC_validate(struct pios_usb_cdc_dev *usb_cdc_dev)
{
    return usb_cdc_dev->magic == PIOS_USB_CDC_DEV_MAGIC;
}

#if defined(PIOS_INCLUDE_FREERTOS)
static struct pios_usb_cdc_dev *PIOS_USB_CDC_alloc(void)
{
    struct pios_usb_cdc_dev *usb_cdc_dev;

    usb_cdc_dev = (struct pios_usb_cdc_dev *)pios_malloc(sizeof(struct pios_usb_cdc_dev));
    if (!usb_cdc_dev) {
        return NULL;
    }

    memset(usb_cdc_dev, 0, sizeof(struct pios_usb_cdc_dev));
    usb_cdc_dev->magic = PIOS_USB_CDC_DEV_MAGIC;
    return usb_cdc_dev;
}
#else
static struct pios_usb_cdc_dev pios_usb_cdc_devs[PIOS_USB_CDC_MAX_DEVS];
static uint8_t pios_usb_cdc_num_devs;
static struct pios_usb_cdc_dev *PIOS_USB_CDC_alloc(void)
{
    struct pios_usb_cdc_dev *usb_cdc_dev;

    if (pios_usb_cdc_num_devs >= PIOS_USB_CDC_MAX_DEVS) {
        return NULL;
    }

    usb_cdc_dev = &pios_usb_cdc_devs[pios_usb_cdc_num_devs++];

    memset(usb_cdc_dev, 0, sizeof(struct pios_usb_cdc_dev));
    usb_cdc_dev->magic = PIOS_USB_CDC_DEV_MAGIC;

    return usb_cdc_dev;
}
#endif /* if defined(PIOS_INCLUDE_FREERTOS) */

static void PIOS_USB_CDC_DATA_EP_IN_Callback(void);
static void PIOS_USB_CDC_DATA_EP_OUT_Callback(void);
static void PIOS_USB_CDC_CTRL_EP_IN_Callback(void);

static uint32_t pios_usb_cdc_id;

/* Need a better way to pull these in */
extern void(*pEpInt_IN[7]) (void);
extern void(*pEpInt_OUT[7]) (void);

int32_t PIOS_USB_CDC_Init(uint32_t *usbcdc_id, const struct pios_usb_cdc_cfg *cfg, uint32_t lower_id)
{
    PIOS_Assert(usbcdc_id);
    PIOS_Assert(cfg);

    struct pios_usb_cdc_dev *usb_cdc_dev;

    usb_cdc_dev = (struct pios_usb_cdc_dev *)PIOS_USB_CDC_alloc();
    if (!usb_cdc_dev) {
        goto out_fail;
    }

    /* Bind the configuration to the device instance */
    usb_cdc_dev->cfg = cfg;
    usb_cdc_dev->lower_id = lower_id;

    pios_usb_cdc_id  = (uint32_t)usb_cdc_dev;

    /* Bind lower level callbacks into the USB infrastructure */
    pEpInt_OUT[cfg->ctrl_tx_ep - 1] = PIOS_USB_CDC_CTRL_EP_IN_Callback;
    pEpInt_IN[cfg->data_tx_ep - 1]  = PIOS_USB_CDC_DATA_EP_IN_Callback;
    pEpInt_OUT[cfg->data_rx_ep - 1] = PIOS_USB_CDC_DATA_EP_OUT_Callback;

    *usbcdc_id = (uint32_t)usb_cdc_dev;

    return 0;

out_fail:
    return -1;
}


static void PIOS_USB_CDC_RegisterRxCallback(uint32_t usbcdc_id, pios_com_callback rx_in_cb, uint32_t context)
{
    struct pios_usb_cdc_dev *usb_cdc_dev = (struct pios_usb_cdc_dev *)usbcdc_id;

    bool valid = PIOS_USB_CDC_validate(usb_cdc_dev);

    PIOS_Assert(valid);

    /*
     * Order is important in these assignments since ISR uses _cb
     * field to determine if it's ok to dereference _cb and _context
     */
    usb_cdc_dev->rx_in_context = context;
    usb_cdc_dev->rx_in_cb = rx_in_cb;
}

static void PIOS_USB_CDC_RegisterTxCallback(uint32_t usbcdc_id, pios_com_callback tx_out_cb, uint32_t context)
{
    struct pios_usb_cdc_dev *usb_cdc_dev = (struct pios_usb_cdc_dev *)usbcdc_id;

    bool valid = PIOS_USB_CDC_validate(usb_cdc_dev);

    PIOS_Assert(valid);

    /*
     * Order is important in these assignments since ISR uses _cb
     * field to determine if it's ok to dereference _cb and _context
     */
    usb_cdc_dev->tx_out_context = context;
    usb_cdc_dev->tx_out_cb = tx_out_cb;
}

static void PIOS_USB_CDC_RxStart(uint32_t usbcdc_id, uint16_t rx_bytes_avail)
{
    struct pios_usb_cdc_dev *usb_cdc_dev = (struct pios_usb_cdc_dev *)usbcdc_id;

    bool valid = PIOS_USB_CDC_validate(usb_cdc_dev);

    PIOS_Assert(valid);

    if (!PIOS_USB_CheckAvailable(usb_cdc_dev->lower_id)) {
        return;
    }

    // If endpoint was stalled and there is now space make it valid
    PIOS_IRQ_Disable();
    if ((GetEPRxStatus(usb_cdc_dev->cfg->data_rx_ep) != EP_RX_VALID) &&
        (rx_bytes_avail >= sizeof(usb_cdc_dev->rx_packet_buffer))) {
        SetEPRxStatus(usb_cdc_dev->cfg->data_rx_ep, EP_RX_VALID);
    }
    PIOS_IRQ_Enable();
}

static void PIOS_USB_CDC_SendData(struct pios_usb_cdc_dev *usb_cdc_dev)
{
    uint16_t bytes_to_tx;

    if (!usb_cdc_dev->tx_out_cb) {
        return;
    }

    bool need_yield = false;
    bytes_to_tx = (usb_cdc_dev->tx_out_cb)(usb_cdc_dev->tx_out_context,
                                           usb_cdc_dev->tx_packet_buffer,
                                           sizeof(usb_cdc_dev->tx_packet_buffer),
                                           NULL,
                                           &need_yield);
    if (bytes_to_tx == 0) {
        return;
    }

    UserToPMABufferCopy(usb_cdc_dev->tx_packet_buffer,
                        GetEPTxAddr(usb_cdc_dev->cfg->data_tx_ep),
                        bytes_to_tx);
    SetEPTxCount(usb_cdc_dev->cfg->data_tx_ep, bytes_to_tx);
    SetEPTxValid(usb_cdc_dev->cfg->data_tx_ep);

#if defined(PIOS_INCLUDE_FREERTOS)
    if (need_yield) {
        vPortYield();
    }
#endif /* PIOS_INCLUDE_FREERTOS */
}

static void PIOS_USB_CDC_TxStart(uint32_t usbcdc_id, __attribute__((unused)) uint16_t tx_bytes_avail)
{
    struct pios_usb_cdc_dev *usb_cdc_dev = (struct pios_usb_cdc_dev *)usbcdc_id;

    bool valid = PIOS_USB_CDC_validate(usb_cdc_dev);

    PIOS_Assert(valid);

    if (!PIOS_USB_CheckAvailable(usb_cdc_dev->lower_id)) {
        return;
    }

    if (GetEPTxStatus(usb_cdc_dev->cfg->data_tx_ep) == EP_TX_VALID) {
        /* Endpoint is already transmitting */
        return;
    }

    PIOS_USB_CDC_SendData(usb_cdc_dev);
}

static void PIOS_USB_CDC_DATA_EP_IN_Callback(void)
{
    struct pios_usb_cdc_dev *usb_cdc_dev = (struct pios_usb_cdc_dev *)pios_usb_cdc_id;

    bool valid = PIOS_USB_CDC_validate(usb_cdc_dev);

    PIOS_Assert(valid);

    PIOS_USB_CDC_SendData(usb_cdc_dev);
}

static void PIOS_USB_CDC_DATA_EP_OUT_Callback(void)
{
    struct pios_usb_cdc_dev *usb_cdc_dev = (struct pios_usb_cdc_dev *)pios_usb_cdc_id;

    bool valid = PIOS_USB_CDC_validate(usb_cdc_dev);

    PIOS_Assert(valid);

    uint32_t DataLength;

    /* Get the number of received data on the selected Endpoint */
    DataLength = GetEPRxCount(usb_cdc_dev->cfg->data_rx_ep);
    if (DataLength > sizeof(usb_cdc_dev->rx_packet_buffer)) {
        usb_cdc_dev->rx_oversize++;
        DataLength = sizeof(usb_cdc_dev->rx_packet_buffer);
    }

    /* Use the memory interface function to read from the selected endpoint */
    PMAToUserBufferCopy((uint8_t *)usb_cdc_dev->rx_packet_buffer,
                        GetEPRxAddr(usb_cdc_dev->cfg->data_rx_ep),
                        DataLength);

    if (!usb_cdc_dev->rx_in_cb) {
        /* No Rx call back registered, disable the receiver */
        SetEPRxStatus(usb_cdc_dev->cfg->data_rx_ep, EP_RX_NAK);
        return;
    }

    uint16_t headroom;
    bool need_yield = false;
    uint16_t rc;
    rc = (usb_cdc_dev->rx_in_cb)(usb_cdc_dev->rx_in_context,
                                 usb_cdc_dev->rx_packet_buffer,
                                 DataLength,
                                 &headroom,
                                 &need_yield);

    if (rc < DataLength) {
        /* Lost bytes on rx */
        usb_cdc_dev->rx_dropped += (DataLength - rc);
    }

    if (headroom >= sizeof(usb_cdc_dev->rx_packet_buffer)) {
        /* We have room for a maximum length message */
        SetEPRxStatus(usb_cdc_dev->cfg->data_rx_ep, EP_RX_VALID);
    } else {
        /* Not enough room left for a message, apply backpressure */
        SetEPRxStatus(usb_cdc_dev->cfg->data_rx_ep, EP_RX_NAK);
    }

#if defined(PIOS_INCLUDE_FREERTOS)
    if (need_yield) {
        vPortYield();
    }
#endif /* PIOS_INCLUDE_FREERTOS */
}

static uint16_t control_line_state;
RESULT PIOS_USB_CDC_SetControlLineState(void)
{
    struct pios_usb_cdc_dev *usb_cdc_dev = (struct pios_usb_cdc_dev *)pios_usb_cdc_id;

    bool valid = PIOS_USB_CDC_validate(usb_cdc_dev);

    if (!valid) {
        /* No CDC interface is configured */
        return USB_UNSUPPORT;
    }

    uint8_t wValue0 = pInformation->USBwValue0;
    uint8_t wValue1 = pInformation->USBwValue1;

    control_line_state = wValue1 << 8 | wValue0;

    return USB_SUCCESS;
}

static bool PIOS_USB_CDC_Available(uint32_t usbcdc_id)
{
    struct pios_usb_cdc_dev *usb_cdc_dev = (struct pios_usb_cdc_dev *)usbcdc_id;

    bool valid = PIOS_USB_CDC_validate(usb_cdc_dev);

    PIOS_Assert(valid);

    return PIOS_USB_CheckAvailable(usb_cdc_dev->lower_id) &&
           (control_line_state & USB_CDC_CONTROL_LINE_STATE_DTE_PRESENT);
}

static struct usb_cdc_line_coding line_coding = {
    .dwDTERate   = htousbl(57600),
    .bCharFormat = USB_CDC_LINE_CODING_STOP_1,
    .bParityType = USB_CDC_LINE_CODING_PARITY_NONE,
    .bDataBits   = 8,
};

uint8_t *PIOS_USB_CDC_SetLineCoding(uint16_t Length)
{
    struct pios_usb_cdc_dev *usb_cdc_dev = (struct pios_usb_cdc_dev *)pios_usb_cdc_id;

    bool valid = PIOS_USB_CDC_validate(usb_cdc_dev);

    if (!valid) {
        /* No CDC interface is configured */
        return NULL;
    }

    if (Length == 0) {
        /* Report the number of bytes we're prepared to consume */
        pInformation->Ctrl_Info.Usb_wLength = sizeof(line_coding);
        pInformation->Ctrl_Info.Usb_rLength = sizeof(line_coding);
        return NULL;
    } else {
        /* Give out a pointer to the data struct */
        return (uint8_t *)&line_coding;
    }
}

const uint8_t *PIOS_USB_CDC_GetLineCoding(uint16_t Length)
{
    struct pios_usb_cdc_dev *usb_cdc_dev = (struct pios_usb_cdc_dev *)pios_usb_cdc_id;

    bool valid = PIOS_USB_CDC_validate(usb_cdc_dev);

    if (!valid) {
        /* No CDC interface is configured */
        return NULL;
    }

    if (Length == 0) {
        pInformation->Ctrl_Info.Usb_wLength = sizeof(line_coding);
        return NULL;
    } else {
        return (uint8_t *)&line_coding;
    }
}

struct usb_cdc_serial_state_report uart_state = {
    .bmRequestType = 0xA1,
    .bNotification = USB_CDC_NOTIFICATION_SERIAL_STATE,
    .wValue      = 0,
    .wIndex      = htousbs(1),
    .wLength     = htousbs(2),
    .bmUartState = htousbs(0),
};

static void PIOS_USB_CDC_CTRL_EP_IN_Callback(void)
{
    struct pios_usb_cdc_dev *usb_cdc_dev = (struct pios_usb_cdc_dev *)pios_usb_cdc_id;

    bool valid = PIOS_USB_CDC_validate(usb_cdc_dev);

    PIOS_Assert(valid);

    /* Give back UART State Bitmap */
    /* UART State Bitmap
     *   15-7: reserved
     *      6:  bOverRun    overrun error
     *      5:  bParity     parity error
     *      4:  bFraming    framing error
     *      3:  bRingSignal RI
     *      2:  bBreak      break reception
     *      1:  bTxCarrier  DSR
     *      0:  bRxCarrier  DCD
     */
    uart_state.bmUartState = htousbs(0x0003);

    UserToPMABufferCopy((uint8_t *)&uart_state,
                        GetEPTxAddr(usb_cdc_dev->cfg->ctrl_tx_ep),
                        sizeof(uart_state));
    SetEPTxCount(usb_cdc_dev->cfg->ctrl_tx_ep, PIOS_USB_BOARD_CDC_MGMT_LENGTH);
    SetEPTxValid(usb_cdc_dev->cfg->ctrl_tx_ep);
}

#endif /* PIOS_INCLUDE_USB_CDC */
